The zero product rule tells you that a product will be zero if and only if one of the factors is zero. These binomial factors are zero when x has a value that is opposite the constant of the binomial.
x +6 = 0 ⇒ x = -6
x -4 = 0 ⇒ x = 4
x +2 = 0 ⇒ x = -2
The zeros of the function are the x-values -6, -2, and 4.
